In an IEEE 802.16e system network which is being used, capability negotiation is performed between a Mobile Station (MS) and a Base Station (BS) after an initial ranging procedure during initial network entry. The capability negotiation is carried out during initialization of the MS by transmitting and receiving a Subscriber Station Basic Capability Request (SBC-REQ) message and a Subscriber Station Basic Capability Response (SBC-RSP) message.
If the MS performs handoff to another BS after entering a network, the MS may acquire System Information (SI) of a handover target BS through Downlink Channel Descriptor (DCD)/Uplink Channel Descriptor (UCD) information of a neighbor BS advertisement (MOB_NBR-ADV) message of a serving BS.
The MS performs negotiation about a security procedure for handoff optimization during ranging with the target BS. Accordingly, additional security negotiation through the SBC-REQ message and the SBC-RSP message need not necessarily be performed.
However, if the handover target BS is different in capability from the serving BS, it is desirable that the handover target BS inform the MS of capability elements which should be additionally updated, through a ranging response (RNG-RSP) message in a handover ranging process with the MS.